1. Field of the Invention
The present invention relates to a receiver for broadcast radio waves.
2. Description of the Related Background Art
In conventional broadcast receivers, it is widely adopted to detect the reception status of radio waves from other stations while receiving a radio wave from one station. Such an operation makes it possible to provide only the stations of favorable reception status for user's selection when the user switches from a currently-receiving station to another. This means an improved operability of the receivers upon station selections. The operation also makes feasible the technique of so-called frequency diversity, in which the reception system is switched to the radio wave from another station that broadcasts the same program when the currently-receiving radio wave deteriorates in reception status.
Nevertheless, when the operation described above is implemented in a so-called one-tuner receiver which performs such reception processing as high frequency amplification, tuning, and detection in a single set alone, various contrivances are required for precluding interruptions of the currently-receiving broadcast. For example, in the cases of television broadcast radio waves, periods of no picture signal transmission, or vertical blanking intervals, have been conventionally used to detect the radio waves from other stations.
However, in the case of the digital broadcast in which the video signal and the like signals are converted to digital data that is continuous in terms of time series, information associated with the vertical blanking period also is converted to digital data. Therefore, if it is attempted to adopt a process for detecting other-station radio waves that utilizes the vertical blanking intervals like the detection process for the analog television broadcast, that would result in undesirable droping of data.